Study on Reduction Stripping Kinetics of Ce4+ Using a Constant Interfacial Area Cell with Laminar Flow

The reduction stripping kinetics of Ce4+ by HEH/EHP was studied by a constant interfacial area cell with laminar flow. The effects of stirring speed, temperature, specific interfacial area, Ce4+ concentration in the organic phase, free extractant concentration in the organic phase, HCl concentration, and H2O2 concentration on the stripping rate were investigated. The control mode and control steps of stripping process were judged. The kinetic equation of stripping was derived. The mechanism of stripping process was discussed. The results show that the stripping process is controlled by both diffusion and interfacial chemical reaction. The apparent activation energy Ea was calculated using Arrhenius’s formula. The kinetic equation of Ce4+ reduction stripping is R = k[Ce4+](o)1.08[HEH/EHP](o)−1.03[H+](a)0.99[H2O2](a)0.53, and the apparent rate constant k is 10−3.66 (mol−0.57·L0.57)/min.